If you're reading this, you're either:
A) Aware the internet exists and how to navigate it
B) Reading this off one of the many pieces of paper I have printed off and placed on windshields of cars in a 0.5 mile radius of my office.
C) Capable of beaming my thoughts directly from my brain into yours, and most likely have already enslaved humanity to work in your plutonium mines
I'm going with A.
So you should probably be aware of Godwin's Law. But if you're not, here's a quick refresher.
Godwin's Law is a 20 year old adage stating "As a Usenet discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1."
It's basically a nerdy way to say that if you're arguing or discussing something on the internet--originally in Usenet groups, now including anywhere online that allows you to write a comment--eventually one party will refer to other as "ZOMG ur such a Nazi!"
It's also become an extension of Godwin's Law that the first party in an argument to bring up Nazis, Hitler, Communist China, Bill O' Reilly, etc as a comparison to your opponents argument or even a point of reference automatically is declared the "loser" of the argument/debate and must go back to their internet cave in shame.
Personally, I think that if the rest of the world acted like the internet does in reference to Godwin's Law, it would be a better place.
Godwin's Law is constantly evolving (hence the Communist China & O'Reilly addendums) by way of popular usage.
The same principle behind it also morphs into different sub-groups of society and adapts accordingly.
One of these variations is to doubt another's salvation or authenticity. For example, person A doesn't do something person B likes...they must be a bad Christian. Or Christianity as a whole is garbage, etc. This is most prevalent in interactions between Christians. See example:
Insane? Probably so.
But it doesn't just stop at rogue barking dogs. People slap others with this reductionist argument all the time.
We take and apply what we assume should be Christian behaviors or attitudes and then when someone who we expect should exhibit these behaviors does not do so; we question their motives, their persona, their faithfulness, their very salvation.
The fun thing is, this one seems to vary inversely with the pettiness of the concern. That is, the more petty the concern the more likely an angry person will invoke your failures as a Christian.
emailsfromcrazypeople.com calls it "The Crazy Cross" rule.
When this particular card is played, the same social response that Godwin's Law dictates should be invoked: You lose.
No matter the relevancy of your original concern, the validity of your argument or the point you were trying to make; as soon as you bring up Hitler, Communists, O'Reilly, or a phrase along the lines of "well you're just not a good/real/right/faithful/believing/mature/etc Christian," you have lost.
Admit your defeat, retire to your cave in shame, and don't do it again.